1. Technical Field of the Invention
The invention relates generally to communication systems; and, more particularly, it relates to integration of components within communication devices employed within such communication systems.
2. Description of Related Art
Communication systems are known to support wireless and wire lined communications between wireless and/or wire lined communication devices. Such communication systems range from national and/or international cellular telephone systems to the Internet to point-to-point in-home wireless networks. Each type of communication system is constructed, and hence operates, in accordance with one or more communication standards. For instance, wireless communication systems may operate in accordance with one or more standards including, but not limited to, IEEE 802.11, Bluetooth, advanced mobile phone services (AMPS), digital AMPS, global system for mobile communications (GSM), code division multiple access (CDMA), local multi-point distribution systems (LMDS), multi-channel-multi-point distribution systems (MMDS), radio frequency identification (RFID), Enhanced Data rates for GSM Evolution (EDGE), General Packet Radio Service (GPRS), and/or variations thereof.
Depending on the type of wireless communication system, a wireless communication device, such as a cellular telephone, two-way radio, personal digital assistant (PDA), personal computer (PC), laptop computer, home entertainment equipment, RFID reader, RFID tag, et cetera communicates directly or indirectly with other wireless communication devices. For direct communications (also known as point-to-point communications), the participating wireless communication devices tune their receivers and transmitters to the same channel or channels (e.g., one of the plurality of radio frequency (RF) carriers of the wireless communication system or a particular RF frequency for some systems) and communicate over that channel(s). For indirect wireless communications, each wireless communication device communicates directly with an associated base station (e.g., for cellular services) and/or an associated access point (e.g., for an in-home or in-building wireless network) via an assigned channel. To complete a communication connection between the wireless communication devices, the associated base stations and/or associated access points communicate with each other directly, via a system controller, via the public switch telephone network, via the Internet, and/or via some other wide area network.
For each wireless communication device to participate in wireless communications, it includes a built-in radio transceiver (i.e., receiver and transmitter) or is coupled to an associated radio transceiver (e.g., a station for in-home and/or in-building wireless communication networks, RF modem, etc.). As is known, the receiver is coupled to an antenna and includes a low noise amplifier, one or more intermediate frequency stages, a filtering stage, and a data recovery stage. The low noise amplifier receives inbound RF signals via the antenna and amplifies then. The one or more intermediate frequency stages mix the amplified RF signals with one or more local oscillations to convert the amplified RF signal into baseband signals or intermediate frequency (IF) signals. The filtering stage filters the baseband signals or the IF signals to attenuate unwanted out of band signals to produce filtered signals. The data recovery stage recovers raw data from the filtered signals in accordance with the particular wireless communication standard.
As is also known, the transmitter includes a data modulation stage, one or more intermediate frequency stages, and a power amplifier. The data modulation stage converts raw data into baseband signals in accordance with a particular wireless communication standard. The one or more intermediate frequency stages mix the baseband signals with one or more local oscillations to produce RF signals. The power amplifier amplifies the RF signals prior to transmission via an antenna.
While transmitters generally include a data modulation stage, one or more IF stages, and a power amplifier, the particular implementation of these elements is dependent upon the data modulation scheme of the standard being supported by the transceiver. For example, if the baseband modulation scheme is Gaussian Minimum Shift Keying (GMSK), the data modulation stage functions to convert digital words into quadrature modulation symbols, which have a constant amplitude and varying phases. The IF stage includes a phase locked loop (PLL) that generates an oscillation at a desired RF frequency, which is modulated based on the varying phases produced by the data modulation stage. The phase modulated RF signal is then amplified by the power amplifier in accordance with a transmit power level setting to produce a phase modulated RF signal.
As another example, if the data modulation scheme is 8-PSK (phase shift keying), the data modulation stage functions to convert digital words into symbols having varying amplitudes and varying phases. The IF stage includes a phase locked loop (PLL) that generates an oscillation at a desired RF frequency, which is modulated based on the varying phases produced by the data modulation stage. The phase modulated RF signal is then amplified by the power amplifier in accordance with the varying amplitudes to produce a phase and amplitude modulated RF signal.
As yet another example, if the data modulation scheme is x-QAM (16, 64, 128, 256 quadrature amplitude modulation), the data modulation stage functions to convert digital words into Cartesian coordinate symbols (e.g., having an in-phase signal component and a quadrature signal component). The IF stage includes mixers that mix the in-phase signal component with an in-phase local oscillation and mix the quadrature signal component with a quadrature local oscillation to produce two mixed signals. The mixed signals are summed together and filtered to produce an RF signal that is subsequently amplified by a power amplifier.
As the desire for wireless communication devices to support multiple standards continues, recent trends include the desire to integrate more functions on to a single chip. However, such desires have gone unrealized when it comes to implementing baseband and RF on the same chip for multiple wireless communication standards. In addition, many components and/or modules within the components employed within such communication devices and wireless communication devices include many off-chip elements.
FIG. 4 is a diagram illustrating an embodiment 400 of a prior art implementation of an LNA. An input voltage, Vin, is provided across an input inductor (L3) and then to two separate capacitors, C1 and C2. The outputs from these two separate capacitors, C1 and C2, are provided to two other capacitors, C3 and C4, and subsequently to the gates of a first pair of transistors (M1 and M2). A second pair of transistors (M3 and M4) is implemented such that the drains of the first pair of transistors (M1 and M2) are coupled to the sources of the second pair of transistors (M3 and M4). The gates of the second pair of transistors (M3 and M4) are provided a bias voltage level (Vbias2). Two separate resistors, R1 and R2, are connected between the gates of the first pair of transistors (M1 and M2) and another bias voltage level (Vbias1). Two separate inductors, L1 and L2, are connected between the drains of the second pair of transistors (M3 and M4) to a power supply voltage level (Vdd0). Two source inductors are connected between the sources of the first pair of transistors (M1 and M2) to ground. As can also be seen, the node between capacitor, C1, and capacitor, C3, is connected to the source of one transistor (M2) within the pair of transistors (M1 and M2), and the node between capacitor, C2, and capacitor, C4, is connected to the source of the other transistor (M1) within the first pair of transistors (M1 and M2). If desired, shunt capacitors can be implemented as well as depicted in the diagram (e.g., using dotted lines). For example, one shunt capacitor can be implemented each of the sides of capacitor, C1, and capacitor, C2, respectively.
This prior art approach provides a relatively high linearity. It also provides a wide 100Ω differential impedance for the input matching purpose, as well as a good noise figure while maintaining relatively low power consumption. However, this prior art approach also requires off-chip source inductors for providing a better noise figure. Moreover, a relatively large number of off-chip components (e.g., 5 including 2 capacitors [C1, C2], 2 source inductors, and 1 input indictor) generally leads to a higher manufacturing cost than is desirable, and this also leads to a higher form factor (e.g., a larger device occupying larger real estate). These off-chip components are also depicted using a dashed line.